Controller for electric motors and similar devices.



H. W. LEONARD. I CONTROLLER FOR ELECTRIC MOTORS AND SIMILAR DEVICES.APPLIOATIQN FILED MAY 17, 1901. RENEWED JULY 22, 1909.

1,077,6 1 3. Patented Nov. 4, 1913.

ITNESSES 'INVENTOR MJMW. awfl g wwm ATTORNEYS.

Original-application filed m 11, 1902, Serial Ho.1 65 ,061i Dividedand'this application filed-May 17,19o7,

'iUNITED sm-Tns PATENT orator. 1

M15118 WARDLIEONAIRDK, or BRONXVILLE, NEW YORK.

Specification Letters Patent.

CONTROLLER. FOB Emc'rmo Morons aim SIMILAR nninicns.

Patented lVov. 4, 1913.

Serial No. 374,129. Renewed July 22, 1909. Serial No. 509,063.

To all whom ii concern Be it known that I, HARRY When Laos Am), acitizen of the United States, residing at Bronxville, in thecountyof\Vestchester 5 and State ofNew York, have invented certainne'wand usefuLImprovementsin Control-lersfor Electric Motors and Similar Deavices, of which the following is a full, clear,

and exact spe'cificationi. This application is a division of mypendingapplication for improvement in controllers for electric motors andsimilar devices, filed July 11, 1903, Serial No. 165061.

[My invention relates principally-to-the devices employed for startingand regula'ting the speed 0telectric motors, and to the Y'devices'employedfor protecting such devices and the motor against damage due toabnormal variations in the circnit;

Heretofore such. devices, and particularly 'tlre"st'a-rters and field,controllers, were preferably entirely separate pieces of apparatus 23'devices areirequently the canse'of ingury ;the improperoperation of theseparate lleand were operated independently of ach 1 other. Sucharrangement of the controling to the motor and controlling means due tovices and tocarelessenss or ignorance on the part of, the operator.

80 7 a motor starter, speed regulator and auto- One object ofmyinvention is to combine -mat-ic 'protectiye devices with interlocking mans, whereby the'several elements constitutinga controller can only beoperated in the proper sequence to start and regulate a. motor, and sothat the protective devices.

will always be in a position to respond to abnormal-changes in the motorcircuit, and

whereby the'starting of a motor and the conis to say,.the controllingapparatus and the motor will be entirely safe, e-fen in the hands-ofinexperienced, careless or ignorant opera-tors;

' .tric motors, it is very desirable that there startedland brought, tofull speed, and

be proyide'd a simple, efiicient, reliable, inexpensive and compact formof controlling apparatus by means of which the motor can later,ifnecesSary perated at any speed over as widela'range of speed aspossible: On accountof the efficiency and simplicity ofthe method, it isvery desirable to secure the speed variation bv-varvinr the field lessconstant.

trolof its speediwillbe foolproof; that.

In; the operation of many kinds of ma- I chine tools and otherappliances-by elec-- strength of the motor. Electricmotors have now beenso far improved as regards freedom from sparking, that they require veryllttle attention in operation, even when the extensively employed in theoperation of machine tools and in performing many other .lzinds of workwhere a wide'range of 115 ofvalue, and especially where the t quevariesinversely as the speed to'st ch an extent that the power of themotor is more or The controlling apparatus for such motors eed field'isvaried overa very wide'range, and hence 1n the-future these motors willbe very should have the following characteristics First, a'in overloadprotective device which circuitto the motor if under'any conditions ofstarting or operation a current'greater than a certain 'predeterininableamount should flow injthe motor circuit. Second.

will positively'and instantaneously open the v this overload device mustbe such that the 7 motor can be safely-and simply'started up again bythe operator without loss of time and without expense. Third, ano-ivolta'ge release, or clectroresponsive .device'whichwilhautomatically act if the supply. voltage fails, .or isreduced toavery low-point,to

protect the motor-againsttherisks due to" a sudden rise to 'fullvolt-age, andsuchfnovoltage ,device shall be dependent'upon the and'overa wide range, so that, for example, a cutting tool can be worked in themost efiicient ananner at any speed and out within the capacity of themotor. Fifth, astarti'ng rheostat.

Sixth, interlocking or fu1ic-, tionally ,related mechanism, orcqnivalent arrangement of mechanism, which will in-. i

sure the proper sequence of adjustments,

and \v'herebv-it will be impomibl'e for the operator to start the motorwhilethe motor has an improperly weakened field. \Yhile thisinterlocking or equivalent mechanism is preferably arranged diroctlybctw ecn the speed controlling device and the motor starter, itisevident that it"may be applied between any device controlling 'the speedcontroller and any device which controls the current passing through themotor armature, such as a switch in series with the1no- V tor armature ad starter.

The desirable features above 'setforth are embodied inthe-controllerinvented by me,

. and in carrying my invention into .efi'ect,

I preferably employ a .no'-voltage? switch and an overload switch, whichare functionally connected,'.and [the no-voltage switch serving also asthe contact arm of the starting rheostat. f Both of these switches arepreferablyspring actuated so as to' tendto move to the/open circuitposition, and the overload switch is'preferably moved to its closedposition by the movement.of the no-voltage switch toitsstartingrpositionw The overload switch is held closed bya latch whichis released through the agency of an electror'es'ponsive device which isset to" respond to a 'p rede termined flow. of current, and theno-voltage switch may be held by a similar form of latch, which isreleased throughthe agency of an electroresponsive device which respondto an abnormal 'drop'in -the volt-,

ploy a rheostat which is designed to'- beconnected in series with thefield winding of the motor. This rheostat preferably Has a large numberof steps so asto secure great refinement in the graduation' of'thefieldstrength" of a motor, andlth'us secure per-.-

fect control o'f-the speed of the motor armor ture. Between theope-rating devices of the" starting rheostat and the field rheostat, I

prov'ide in my preferred form'an interlocking: or otherwise functionallyrelated device, the' function of which is to so relate themotorstart-ing switch or starting rheostat to the fieldcont rollingmeans, that the starting, of the motor when the field is 7 too weak" tosecure the best results, is

avoided. This interlocking or 'functionally relating deviceconsequentlyinsures; that the motor field will'always have a properstrength when the motor is'started. My invention is'ill-ustrated in theaccompanying drawing, in which the figure a diagram illustrating oneform of my invention.

Referring to the drawing, A indicates the coiitact arm of the motorstarter, and a the contact buttons of the resistance" sections.

B is the overload switch which enters spring contact blades 6. A and Bare pivoted on. a common stud, and a spring a coiled around the stud;and having itsrends secured to the switcharms, tends to drive saidarmstoward each other. is'a'rubher or. otheribuiler 'oxr swit iih: arm,Bjagainst whichfarm A strikes when eitlter armis Y propelled by spring,and to which switch 13 moved to its closedposition by arm A.

is provided with an armature e which is held by the magnetism ofmagnet-E in the form-shown in Fig. 1 when the. arm is. initsfinal'positi'on. Upon an abnormal drop in the voltage, the magnetismof magnet E will be insuflicient to holdleverA against the pull of itsspring and hencethat lever will then return to its initial position. Ifan overload should occur switchB would be released and it would open;the circuit'and move toward arm A. until arrested by the buffer b. Thisopening of switch B also deenergizes magnet gE, and in order to closeswitch-Bagain, arm A is returned to its starting position-the positionshownby dotted'lines in the drawings. C-is the operating device for thefield rheostat, the resistance 0' of which: maybe nameled toa metalplate. Thisoperat'ing device is securedto ashaft which has s ecuredtoits op osite-qid the contactblade a.

r n; the. particular form-"shown m the- -drawing,'theco ntact arm of thestarter, or an extension thereof, is so arranged that whenit is. moved'finalp'osition to the initial position, its ges with the fieldcontroller and operates i so contact arm of the starter reachesitsinitial= position, the resistance. of the" field rheostatwill be all cutout of circuit,- and so places the operating device of -the'r fieldrheostat in proper-position for. again startingthe motor. Inthis formof-construction, A; is-. l-theekten s'ion of arm'A, and C' is a pivotedlever having its free arminf thepath of movement ofextension A, and theother end is a-t'oo'thed are m 'whlchf meshes with spur ear :2: on theshaft of operating de vice In practice, the contact buttons of a. fieldrheostat are arranged to form almost a complete circle, so that in movinits contact blade from one extreme to t e other, 7 the operatingdevice'and shaft make nearly a complete revolution. For thisreason, thetoothed arc wl will be provided with the 1 same number 0 teeth as spurgear in and be so proportione ,thatin moving device O from one extremeposition toith'e other, arm C- willmove a istance corresponding totheangular movem t-of arm A. from its iiii- V tial position to i finalpoaition. 1 In the po-. sition shown in ulljlufe's', arm A Aiis inthe"final position, and-all the-resistance of the field rheostat is cut out;Contact arm' A. and extension A" are free to move back that when thei'pw eie and forthwithout-striking lever C when no resistance c is incircuit If device is rotated to cut in resistance, leyer C will I movetoward arm A, and should arm A be released and propelled toward itsinitial position, arm A will encounter lever G and drive thatleverbackto its initial position, so that thefapparatus will be inproper position to aga1n start the motor.

-It' will also be noted that when arm A is in its initial onstartinposition, as shown in dotted lines, device cannot be operated to connectresistance a into the-field circuit of the motor since arm Atstands-lathe path of lever (1" and locks it, and hence device C againstmovement.-

In some casesthe motor ma ries winding on-.the field, so thwillbeafiected by the armature current.

' I have shown the no-voltage coil E, in

Fig. L es-connected acrossthe motor arma ture terminals with aresistance R in series have a se at the field \vithit; r a

Although-I haveshown a specific form of. my;inventio-nih'erein, myinvention may -beembodied in various other; forms of construction, andit will be understood'that my "invention is not-limited to the preciseform hcrcinshow-n and described. i v. My invention is also capable ofuse 'witli currents of different forms and with VB} rious-types' ofmotors, such as motors of-dired or alternating current type. i I Havinthus describ my invention; I 36 declarcltlat what I cla' as'new and de-csire to ecurevby Letters Patent, c p "l- The combination with a motorhaving a shunt field windingy'a .rh eostat in series with saidfieldwinding,-an-additional starting; rheosta'h'means tending to movethe contact arinthereof toward the initial posit-ion and which arnrisdesigned .tobe held -in its final. position; an automatic release forsaidarm which'responds whenthe su plyvolta'ge falls below a certainamount,t e movement vof said contact, ar'm toward the initial positionalso causingthe'movement of the-arm of said 'rheostat in series with'thc 'ficlrl'winding toward the resistance all out position. 2; Thecombination with a motor having a shunt field winding, a rheostat inseries with said field winding, an additional startin; rhcostnt,meanstending to move the contact 'arm'thereof toward the initialposition and which arm is designed to be held in its iinal position, anautomatic release for said arm which responds when the-supply j voltage. falls belowra certain amount, the 50 said contact-arm1when movingtoward the 4 initial ositiommechanicall engaging. the

field ad usting means of sai *rheostat in se ries with" the fieldwinding and actuating the same to'decrease the field resistance in'circuit.

may .be moved independently, of said first 3. The'combination of anelectric motor, a starting resistance having a movable con tact-element,an additional field resistance having a movable-contact element whichnamed element, a no-voltage device for r'etaining 's'aidfirst namedelement in final position, and meanscarried by said first named elementadapted to engage said second element whensaid first element is re-vleased for moving said second element to its initial position. A I 4.The combination'ofan electric motor', a starti switch for closing thearmature circuit 0 the motor, a fieldresistance having a movable'elementfor varying said resistance,- and means for-returning said--elementtoward theresistance all out position by themovement ofsaidstarting switch to,-

ward its open'circuit position. i 5. The combination of a il electric"motor j having a permanentlyclosed local loop conv taining thearmatureflwindigg and a -.fi d winding, a starting switch or connecti gand disconnecting-said" loo vtoandfroxn the supply conductors, a fielresistance having a movable element for varying-said re sistance, andmeans; for returmngsaid element toward the resistance all out positionby the movement of said starting switch toward the open circuitposition. '6.-' The combination ofan electric motor, a-

. starting switch for closing .the armature cir cuit of the motor, afield resistance having a movable elcmentfor varying said resistance,means for returning said=element"to war d the resistance all V outposition by the movement of said starting switch toward the open 'cir-flcuit position, and electro-responsive means for protecting the motorfrom overload.

'L-An electric motor "having a field-winding energized independently ofits armature current, a spring actuated resistance c0n-- trolling switchin series with the motor to no-voltage controlling the automaticmovementof sai'd'switchupon the occurrence of no-voltage, a movableelement forcontrolling the field of-said 'motor, and means forcontrolling the automatic protective movement of said element controlledby the automatic movement of said switch; and. for insuring apropersequence of their relative movement when the starting current ispassed through the-motor'ai'mature;

8.' The combination of a 'mo oi-- starting 'rheos'tathavin a movableelem t,'an additional motor' eld 'rheostat ha.vi1g an independentlymovable element, means in common' forcontrolling the movement ofsaidilzi two elements, a no-voltage electroresponsive device for'normallycounteracting said- ,means, and means "responsiveto overloadcurrent through the motor armature Qfordeiinergraing said device;

armature, electro-magneticm'eans responsive 11oa closed local lcopbandmotor controllingmeans comprising a no-Voltzige magnet and anautomatically movablef'contact ,member, said magnet controlling theautomatic move-.. ment of said member upon. the occurrence of no-voltageto cause the' field relistance tobecut-out, the armatureresistance to becut in and the loop to be disconneqted from the supply circuit. 1- i10.. The combination of a. motor. armaturev resistancehaving acontrollingmovable element,- electromagneticmeans responsive toinc-voltage for retaining said element in its 20 normal position,-means-ior [automatically 1 moving said elementwhen rel ased upon thoccurrence ofno-vo'ltage, and an additional -motor" field resistancehaving a controlling movable element adaptedto be engaged mechanicallyby the automatic movement of I said armature controlling-element and tobe automaticallymoved thereby.

11. "The combination of s'up'p ly conductors, an electric .motor,an'armatu e resistance, a fieldi resistance, means for" connecting thearmature, armature resistance, motor field winding and fieldresistanceii -a closed loop, a movable element for control in thearmatur e resistance, [an independ' nt y movable element for controllingthe fi ldjresistance, and controlling means n coinimon for auto-,maticallyfmoving movable elements upon the occurrence of no v'olta'ge,said means comprising a magnetic winding connected in 40; paralleLkwiththe motor armature and field win ding with reference to the supply con-'du'ctors. I

12. In motor controlling apparatus, the combina tion'- of an automatially jmovable circuit controlling element. a controlling windingtherefornormally energized inde pendently of the current in the motorwind ings and responsive to no-voltage,-a second circuit controllingvelement automaticallymoved by the automatic movement cf the firstelement and means whereby one of said elements controls a fieldresistance otthe factor.

circuit controlling element, a no-volta ge lec- .-t,ro-res onsive deviceconnected in aigallel with he moi-Or windings for .cont rolli' g saidelement, a resistance having aniova le elemen and means whereby saidlatter. element j-s automatically moved by-the first 'namedelement to acircuit protective positionupon the automatic movement of thefirst-named element. 1

gs 14. a motor controlling apparatusi, an

13..Anelectric motor conti'ollirig .ap a ratus compr sing anautomatically mova le'- automatically movable circuit controllingelement, a novoltage device for controlling the automatic movement 'ofsaid element,said device having. the I no-voltage winding" connected inparallel 'withkthe motor windings, a field rheostathaving' an elementfor controlling the field resistance'movable independently of saidfirst-named. element, and means whereby the resistance-30f said fieldrheostat is automatically cut out upon the automatic movement of thefirst-named clement. I

15, T he combination of an electric motor, two independently mountedcircuit control .ling elements, one ofsaid elements being a 30 circuitopening switch. and adapted'to control the armature circuit of'thesaidmotor and the other the magnetic. field of the 1110-; tor, a no-voltagedevice for automatically controlling the'arinature. controlling element5 and means whereby the automaticopening movement of the: latter element"causes the ,protective movement of the field controlling element. 1

1.6. In combinatio'ma motor armature resistance, amotor fieldresistance, "means for: I increasing one'ot said resistancesandfordecreasing the other resistance, and an elec-. t':o-rsponsiv ewinding connected across the motor armature and adapted'to control the.automatic increase of the one resistance and the automaticdecrease-ofthe other resistance. v 4

17. In motor controlling apparatus, two] a independentlymanuallymovable, independ 10o ently mounted, circuit controllingelements, one of said elements adapted to: control .thearmature circuitand the other the field circuit of the motor, and means=f0r'automat-ically moving one of said elements andthereby cause themovement'of'the other of said elements and for insuring a'. propersequence of manual movement of said lemntsl 18. Motor starting and speedregulating a controlling arm therefor, a starting resistanchavingthcicontrol arm biased to the off position andlmovableindependently of the field arm to vary -its resistance, and

arm until. the starting arm..h s'been moved from off position and forcausing the field arm to be moved by'thestarting arm when the latterreturns inire'sponse o" itsbias;

19. lnlcombination. a. 'movahle men'iber, a 120 resistancefcoiitrolledthereby,.-a second 'mov; e meniber, a resistancecontrclled 'by thelatter membcr,-means ope 'atively connecting said members, said latt :rmeniber being lnovablewiththe forme1" amber one'di-' 125 re'ction andthe former member being mov able independently of the lht'ter member inthe opposite. direction, anda magnet for retaining the latter member ina predetermined positioi i apparatus comprising a .field resistance andImeans forpreventing movement of the field opposite direction-to insertthejresis tance .20. In'combination, a movable member, a

resistance controlled thereby, a second mov able member, a resistancecontrolled by thelatter member, means operatively' connecting saidmembers and for rendering said former member ineffective in controllingits resistance while the latter member occupies predetermined positions,said'latter member being movable with the former-member. in

movableindependently of the other member .,in the-opposite directiomanda magnet for;

retaining the latter mber in apredetermined position.

21': In combinat on, a mOVfi ,Dl6 u1crnuUl', a resistance controlledthereby, a second mov able member, a resistance controlled by the,latter member, means operatively "connecting said members, said'lattermember being go movable With the former member .in one di'-.

rection and the former member being movable independentlyof the lattermember in theoppos'ite direction, means \tending to keep-the lattermember in theinitial position thereof, and a magnetforholdingthe latter:member'in a predetermined position.

22. Inccmbinatioma movable member, a resistancecontrolled thereby, asecond m'ov-' able member,- a resistance controlled by thelatter member,means operatively connecting said members to-cause the latter member tomove with the former member in one .di-- rection,.-the former memberbeing movable independently of the latter member in the opposite.direction, said latter'member being adapted to-dec'rease the resistancecontrolled therebywhen it is moved with thefformer P'me'mber and "theformer member being.

-.adapted toT-control' its-'correlated'resistance when it -ismovedndependently he latter 1 '23. In combination, a supplyrcircuit, ami01:-'armlt\ lre connected to said supply eircuit,'a motor fieldconnected to said sup-' gply circnit, a resistance connectedindependently-in series [with the field in said field circuit lto'causethe same current to passthrough the field as passes through saidresistin'ce, a second resistance connected in 10 said armature circuit,a movable member for controlling said field circui t, and a' secondmovableinember forco'ntroiling said armav ture circuit, said secondmember movable in 011s" direction to remove the' resistance.

controlledthereby from' the armature cir controlled thereby in the fieldcircuit.

I 24. In combination, a motor having a'field energized independently ofits current, motor controlling means 0 mpr smg a resistance for-theaemature circuit, a resistance for thefield circuit, two

a manually movable members, said' 'two memone direction-and said formermember being ,second movable member for rendering insaid resistancesand-beingso protectively ,related as to enforce a definite sequence in".their manual operation in accelerating the motor, and means for,automatically moving. 1 at least one of said members to. protectively 7vary said field resistance'upon: no-voltage, tlielast mentioned means;comprising a winding energized independently of Hm current in said fieldwinding.

25. In combination, an electric motor, a field resistance, a movablemember adapted to vary said. field resistance, a second-movable member,means operatively connecting said members, said second movable memberbeingmovable with the other said movable member in onedirectionf-and'the member I adapted to vary the. field resistance beingmpivable independently-of said second movab e member in the op sitedirectiom. means dependent upon the position of said effective the fieldresistance varying. mem-. her in its control of said field resistance,-and. a magnet for retaining the said second movable member 'in apredetermined position.

.265 Incombination, a movable member, a resistance controlled thereby, asecond movable member,,a resistance controlled thereby, means, forconnecting said members to a cause the same to move in one directiontogether but permitting said first movablemember to move in an oppositedirection in dependently of the second. member, and means forautomatically ;-returning both members to their initial position uponthe .release of said second member.

27. In combination, a 'anovable member a resistance controlled "thereby,a second; movable member, a 'Li'esistance, controlled to cause the sameto move'in one direction together. but permitting said vfirst movablememberto move in an opposite direction independently of tbh econdmember, a retaining-magnet for holding thesecond member in apredetermined position, and means for v automatically returning bothmembers to their initial position upon the release of said secondmember.

28. In combination, a supply-circuit, a motor-armature connected in saidsupply circuit, a 'motor-field connected'in said s upgly-circuit, aresistance connected in said eld-circuit, a secondresistance connectedin said armature-circuit, a movable membermovable 'inione direction toremove said field resistance from circuit, a-'second' moy-r vable'member movable in an opposite direction'to removersaid armatureresistance from circuit and a magnet connected in said. supplycircuitfor retaining said second moivable member. ina predetermined position.

29. In combinatmn, a movable member, a resistance cont-rolled thereby, asecond mov- .5 bers cbntrolling "theoperative ccntrblof thereby, meansfor connecting said members- 5' able member, a resistance controlledthere movable i de endently" of said second mem er under. certainoperative conditions.

' .30. In'combinatioina.movable element, a

"resistnnce controlled therebyya second movable elenient, a resistancecontrolled thereby, means tendingto'keep said second movable member inits'init-ialposition, a magnet for retaining sa d second member in apredete'r' minedposition, and means whereby said members will movetogether when said se c= nd member is released by'saidmagnet, saidfirst-"member being movable independently of said second memberundercertain opera-' Live-conditions.

. 31. In-combination,a movablemember, a resistance controlledv thereby,a second movable member, a resistance controlled there'- i-.-=by,restraining means adapted to retain said member is relea sed by saidrestraining... meahs, said first member being movable independently Of'SIII-d second member under second'- 'm'ovable member afpredeterniinedpo's1t1on,...a nd means for causing sald memers to move together whensaid second certain opcrativc conditions.

"- 32. Thecombination of an electric mo tor', astarting'iresistancehaving a movable .contact'element, an' additional field resistancehaving 'which'may .e

a .movable contact element moved independentl of said first naniedelement, a novoltag'e' evice' for retain ng said first named element infinal position, and means carried by said first named'element adaptedto'e-ngage said sec- 4 ply circuit. 45.

endelement when said first element'is' re-- {leased forflmoying saidsecond element to its 'iintialfposition and for' controlling theconnection v of the field circuit with the supr 33 The combination of anelectric motor,

a starting switch for closing-the armature circuitjof the'm'otor, afieldresistance haw a" movablefelement for varying said resistance; and meansfor returning said element; toward. the resistance all-out 'position bythe movement or said starting switch .m aan e t am o hwi 1mg, anarmature resistance,- a .field ance, meansfor connecting the armaturetoward. its open-circuit p0sition, said start:

ing switch beingmovable independently 'ofsaidmovable element. 4 a 2 Y3t-"The combination gef ai of said motor,'.'saidarmatnre'resistance,said v. I field automatic-movement ofsaidmovable'ele closed local loop,almovableelement for the armature resistance and the resistance, andmeans for causing the meat upon the occurrence of novoltagw tors. 35.The combination "of" supply conduc armature resistance "element forautomatid" windr said means comprising ia magnetic connectediii-parallel with the motor win ings with reference to the supplyconductors, an electric motor, aim-armature resist- I ance, an additionalfield resistance, the said armature, armature resistance," motor fieldwinding and field resistance'beingconnec'ted ina'closed loop, a movableelement for controlling the armature resistance and for controlling theconnection; of-said loop to thesuppIy. conductors, an independentlymovable element for controlling the field resistance, means forautomatically opera-f tively moving the" armature resistance element toa protect ve position upon the ciirrenoefof no-voltage,' and meansdependent upon the automatic movement offsaid" cally moving the fieldresistance element 36. The combination of an electric motor,

#1 starting rheostat 'having' a movable el'ement, means 'forautomatically .rnoving said 4 element in. response to. 110-voltage; an'ad di; tional field rheo'stat -h'aving an independently'inovableelement,and means dependcut upon" the automatic movementjof .said ifirst named element for automatically mov- 7 ing ,said second element,the automatic startin rheostat controlling the dis'connection 0 thefield circuit the su ly conductors.-

e' combination of constant. electromotive force supply circuit, a motorconnected therewith and having a field winding,

energized independently of its armature current, controlling meansfOIuSa'ld motor comprising. two 1 operatiyely, protectively.

mutually related resistance-controlling mov- .able members, one ofsaidmembers being adapted to control the circuit of the motor armat'ure,.andthe-other of said members being ada' ted to control the said motor field'windmgyand protective. means comprising a no-voltage winding. energized.1n-

dependently ofthe currents in said arma-- ture and said field windinginsuring that -the field-controlling resistance will be sufxficientlylow in value when the starting current is passed through the. motor.armature.

-38. The'combination of a permanently closed local loop containing thearmature and a field winding of an electric'motor, 'a constantelectromotive force supply circuit, means for connectin said loop to'saidsupsaid field-winding, will be supplied in parjallel and motorcontrolling means for start- 96 movement ofsai'cl movable element. of th:of t the motor ply circuit sothat-t e motor armature and ing upthe'motor armature and for weaken 'ing the motor field strength and forinsuring. a motor field of proper strengthwhen the motor is' started,eaid'mea'ns' comprising a magnetic winding energized independently ofthe armature currentror the field current of said motor and responsiveto no-voltage to .cause a proper field strength for the mo tor when itis started up.

Y 39. In combination, a permanently closed local loop containing a motorarmature, an armature resistance and a field winding, a supply circuit,means for connecting said loop to said supply circuit so that thearmature and armature resistance are in series with each other in abranch circuit, the field winding being in a parallel branch circuit, aresistance adapted to be inserted in the field winding branch circuit, amovable element adapted by its movement to vary both of saidresistances, a winding energized independently of the current in thefield winding branch circuit, said Windingbeing adapted to automaticallycontrol the resistance in the field circuit under certain conditions.

40. The combination of an electric motor having a field windingenergized independently of its armature current, and controlling meanscomprising a no-voltage magnet the winding of said magnet beingconnected in parallel with said field winding, a' movable contactelement adapted to make and break the connection of said field windingto the supply circuit, and a mechanically protectivel relatedindependently movable element adapted by its movement to vary the fieldstrength of the motor. 7

41. The combination of an electric motorling means comprising ano-voltage magnet,

break the connection of said field winding and said no-voltage windingto the supply circuit, and a mechanically protectivelv relatedindependently movable element a apted by its movement to vary the fieldstrength of the motor.

42. A motor having an armature winding and a shunt field winding, anarmature resistance, a field resistance, a no-voltage magnet, and aspring actuated circuit contro ling member adapted to be manually movedto establish the motor actuating current and to cut-out the armatureresistance, and to be restrained by said magnet after said member hasbeen manually moved to cut-out armature resistance, said member beingautomatically moved when released by said magnet upon the occurrence ofno-voltage to insert the armature resistance and to cut-out the fieldresistance.

43. The combination of an electric motor, three movable controllingelements, one being a motor armature switch, one being a motor fieldrheostat, and the third being an automatic magnetic circuit breaker, andmeans for functionally relating said elements. y

In testimony whereof I afiix my signature in presence of 'two witnesses.

HARRY WARD LEONARD. Witnesses: V

- CAROLYN G. LEoNARp,

I/JEONARD KEBLER.

copies of this patent may be obtained for live cents each, by addressingthe Commissioner of Patents. Washington, D. 0."

